Document JvRRnOG1Oagz5Qv3OB9BDw9zZ

Industrial Noise Oims Media An inflammation and in fection of the middle ear Otologist A physician who has spe cialized in surgery and diseases of the ear Otosclerosis Hardening of the ear caused by a growth of bony tissue about the foot plate of the stapes and the oval window of the inner ear It results m a gradual loss of hearing Surgery can often correct this Paracusis Willisii The sensation of a deafened person indicating that he can hear better in a noisy area Pitch That attribute of auditory sensa tion in terms of which sounds may be ordered on a scale extending from low to high Pitch depends primarily upon the frequency of the sound stimulus, but it also depends upon the sound pressure and wave form of the stim ulus Power level The level, m decibels, is 10 times the logarithm to the base 10, of the ratio of a given power to a reference power The reference power must be indicated Presbycusis The hearing loss due to age It is believed by some to be the degen eration of the nerve cells due to the ordinary wear and tear of the ageing process Psychogenic deafness That originat ing in or produced by the mental reaction of an individual to his physical or social en vironment It is sometimes called functional deafness or feigned deafness Recruitment The condition m which an individual perceives an abnormallv rapid increase m loudness as the sound pressure goes up It is usually characteristic of severe sensorineural deafness Response The motion of a device or system (or other output) resulting from an excitation (stimulus) under specified con ditions Reverberation The persistence of sound in an enclosed space, as a result of mul tiple reflections after the sound source has stopped Sensorineural deafness Nerve deaf ness or the lack of sensitivity of the auditory mechanism in the cochlea or paralysis of the acoustic nerve This was formerly called inner ear impairment or perceptive deafness Semicircular canals The special organs of balance that are closely associated with the hearing mechanism and the eighth cranial nerve Simple tone (pure tone)-(a) A simple tone is a sound wave, the instantaneous sound pressure of which is a simple sinusoidal func tion of the time, (b) a simple tone is a sound sensation characterized by its singleness of pitch Single frequency screening test A fast method of rechecking hearing acuity using the 4000 Hz frequency The meas ured value of the threshold at 4000 Hz up to 50 dB can be considered an upper limit for any threshold shift that might have occurred at other lower frequencies Sone A unit of loudness By definition, a simple tone of frequency 1000 Hz, 40 dB above a listener's threshold, produces a loud ness of 1 sone The loudness of any sound that is judged by the listener to be n times that of the 1-sone tone is n sones Sound An oscillation m pressure, stress, particle displacement, particle velocity, etc , which is propagated in an elastic material, in a medium with internal forces (e g , elastic, viscous), or the super-position of such prop agated oscillations Sound is also the sen sation produced through the organs of hear ing--usually bv vibrations transmitted in a material medium, commonly air Sound absorption The change of sound energy into some other form, usually heat, in passing through a medium or on striking a surface In addition, sound absorption is the property possessed by materials and ob jects, including air, of absorbing sound energy Sound analyzer A device for measur ing the band-pressure level or pressurespectrum level of a sound as a function of frequency SOUND level \ weighted sound pres sure level, obtained by the use of metering characteristics and the weighting A, B, or C specified in ASI SI 4-1961 The weight ing employed must always be stated The reference pressure is 0 0002 microbar Sound level meter and octave band ANALYZER Instruments for measuring 1520